Hyper-V FAQ

Applies To: Windows Server 2008

The following are some of the most frequently asked questions about Hyper-V. These questions are based on actual calls and e-mails to Microsoft and might save you time and effort.

Hyper-V deployment

Virtual machines

As of this writing, there are two versions of Hyper-V, with the following version numbers:

  • Beta version = 6.0.6001.17101

  • Release To Market (RTM) = 6.0.6001.18016

  1. On the server running Hyper-V, open Hyper-V Manager and click Help.

  2. Click About Hyper-V Manager…

Alternatively, open a command prompt on the server running Hyper-V and type the following command:

wmic datafile where name=”c:\\windows\\system32\\vmms.exe” get version
  1. On the virtual machine, open the Device Manager Microsoft Management Console (MMC) snap-in and click a “vmBus” device, for example VmBus Network Adapter.

  2. Click Properties.

  3. Click the Driver tab. The number should end in 18016 (the RTM version).

See also: Hyper-V Planning and Deployment Guide (http://go.microsoft.com/fwlink/?LinkID=108560)

Hyper-V requires hardware-assisted virtualization, which is available in processors that include a virtualization option—specifically processors with Intel Virtualization Technology (Intel VT) or AMD Virtualization (AMD-V) technology. Hyper-V also requires that hardware-enforced Data Execution Prevention (DEP) is available and enabled. Specifically, you must enable the Intel XD bit (execute disable bit) or AMD NX bit (no execute bit). The Windows Server catalog shows an up-to-date list of all successfully Hyper-V tested systems (search for Hyper-V as an additional qualification) (http://go.microsoft.com/fwlink/?LinkId=111228). To scan your entire IT environment, and get a report of machines supporting virtualization, use the Microsoft Assessment and Planning Toolkit solution accelerator at: http://technet.microsoft.com/en-us/library/bb977556.aspx (FWLINK NEEDED)

  For older server systems, newer ones not yet in the catalog, or for non-server systems, you can use the following tools to check if your processor supports Hyper-V:

See article 957006 in the Microsoft Knowledge Base (http://go.microsoft.com/fwlink/?LinkID=129503) for information about the support policy for running Microsoft server software in the following supported virtualization environments:

  • Windows Server 2008 with Hyper-V

  • Microsoft Hyper-V Server 2008

  • Server Virtualization Validation Program (SVVP)

    Microsoft supports the Microsoft server software that is running in the supported virtualization environments that are listed in the "More Information" section.

    See also: Microsoft Support Life-Cycle policy (http://go.microsoft.com/fwlink/?LinkId=150563)

Windows PowerShell is not supported on a Server Core installation of Windows Server 2008.

System sleep states, such as Standby and Hibernate, are not supported when the Hyper-V role is enabled.  However, processor power management features are supported with Hyper-V, and will allow the system to automatically scale processor power consumption with system utilization.  The management operating system owns and directs power policy for the virtual machine, and works in conjunction with the hypervisor to direct the system’s processors into low power idle and performance states based on system activity.  System power policy can be configured in the management operating system. There is no power management configuration exposed from Hyper-V.

See the PowerShell scripts available for Hyper-V at the PowerShell management Library for Hyper-V (http://go.microsoft.com/fwlink/?LinkID=135684).

The Hyper-V Update List (http://go.microsoft.com/fwlink/?LinkID=140282) shows the list of software updates and hotfixes for Hyper-V. Updates that are available on Windows Update are indicated, as well as the download location for those that are available at the Microsoft Download Center. In the “Community Content” section of the page, community members also list updates for the following:

  • Windows Server 2008

  • Virtual Machine Manager

  • Virtual Server and Virtual PC

  • Data Protection Manager

The device sharing model in Hyper-V does not expose the physical network adapter of the server running Hyper-V to the virtual machine. The virtual machine can use a network adapter optimized for use in virtual machines, or a legacy Intel/DEC 21140 adapter (depending on the virtual machine configuration setting). If the version of Windows on the server running Hyper-V supports a physical network adapter, you can create a virtual network switch for the virtual machines to use.

See also: Configuring Virtual Networks (http://go.microsoft.com/fwlink/?LinkID=131362)

USB devices are not supported on a virtual machine. Production servers, including servers running Hyper-V, are usually limited in support for USB devices. However, depending on the operating system of the virtual machine, some USB devices such as a mouse, keyboard, and CD/DVD drive that are attached to the server running Hyper-V may be accessible.

As of this writing, the list of virtual devices that are unavailable for virtual machine use because they lack drivers includes the following:

  • Legacy network adapter in Windows Server 2003 with Service Pack 2 (x64) and as Windows XP Professional with Service Pack 2 or Service Pack 3 (x64)

  • SCSI controller in Windows Server 2000 with Service Pack 4 and Windows XP Professional with Service Pack 2 or Service Pack 3 (x86)

We recommend using fixed disks for virtual machines for better performance. Dynamic virtual hard disks are supported, but are not recommended on virtual machines in production, because of the performance issues they can cause. Snapshots are stored using a special kind of virtual hard disk and are supported, but are not recommended in production. For more information about snapshots, see Virtual Machine Snapshots: Frequently Asked Questions (http://go.microsoft.com/fwlink/?LinkID=147648).

Community Additions